"In this Adobe After Effects: Effects A-Z tip, special guest presenter Maltaannon explains some techniques for using the Angle Control effect with basic expressions"
by John Dickinson, http://www.motionworks.com.au

"Use an Expression Controls effect to add a control that you can use to manipulate the values of one or many properties by linking the property to the control using expressions. A single control can affect several properties at once."
(from http://livedocs.adobe.com)

distributing layers in a cylinder using expressions

This expression is customizable, and you can change many things including: the radius of the cylinder, the overall rotation of the cylinder, the spacing vertical spacing between rows of the cylinder, and the amount of layer on each level of the cylinder.